Hard disc drives (HDDs) typically comprise one or more discs, each disc typically having concentric data tracks or another configuration for storing data. Where multiple discs are used, a stack is formed of co-axial discs having generally the same diameter. A transducing head carried by a slider is used to read from and write to a data track on a disc. The slider is carried by a head arm assembly that includes an actuator arm and a suspension assembly, which can include a separate gimbal structure or can integrally form a gimbal. The actuator arm movably positions the slider with respect to the disc. As the disc is spun, the slider glides above the surface of the disc on a small cushion of air. As the slider is positioned closer to the disc, the fly height of the slider can become unstable. This instability can cause the distance between the transducing head and the disc to fluctuate, decreasing reading and writing performance. The instability can become so great that the transducing head can crash into the disc, damaging the transducing head.